What is Drupal?

Drupal is a free and open-source content-management framework written in PHP and distributed under the GNU General Public License. It is used as a back-end framework for at least 2.1% of all Web sites worldwide ranging from personal blogs to corporate, political, and government sites including WhiteHouse.gov and data.gov.uk. It is also used for knowledge management and business collaboration.

How to use this image

If you’d like to be able to access the instance from the host without the container’s IP, standard port mappings can be used:

$ docker run --name some-drupal -p 8080:80 -d drupal

Then, access it via http://localhost:8080 or http://host-ip:8080 in a browser.

There are multiple database types supported by this image, most easily used via Docker networks. In the default configuration, SQLite can be used to avoid a second container and write to flat-files. More detailed instructions for different (more production-ready) database types follow.

When first accessing the webserver provided by this image, it will go through a brief setup process. The details provided below are specifically for the “Set up database” step of that configuration process.

Volumes

By default, this image does not include any volumes. There is a lot of good discussion on this topic in docker-library/drupal#3, which is definitely recommended reading.

There is consensus that /var/www/html/modules, /var/www/html/profiles, and /var/www/html/themes are things that generally ought to be volumes (and might have an explicit VOLUME declaration in a future update to this image), but handling of /var/www/html/sites is somewhat more complex, since the contents of that directory do need to be initialized with the contents from the image.

If using bind-mounts, one way to accomplish pre-seeding your local sites directory would be something like the following:

Adding additional libraries / extensions

This image does not provide any additional PHP extensions or other libraries, even if they are required by popular plugins. There are an infinite number of possible plugins, and they potentially require any extension PHP supports. Including every PHP extension that exists would dramatically increase the image size.

Running as an arbitrary user

Image Variants

The drupal images come in many flavors, each designed for a specific use case.

drupal:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.

This variant is highly recommended when final image size being as small as possible is desired. The main caveat to note is that it does use musl libc instead of glibc and friends, so certain software might run into issues depending on the depth of their libc requirements. However, most software doesn’t have an issue with this, so this variant is usually a very safe choice. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.

To minimize image size, it’s uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).

License

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).